Clinical Microbiology and Antimicrobial Chemotherapy. 2018; vol. 20, N 3: 161-256

Diseases and Pathogens

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):164-171

Pseudomonas aeruginosa: the history of one of the most successful nosocomial pathogens in Russian hospitals

Skleenova E.Yu., Azizov I.S., Shek E.A., Edelstein M.V., Kozlov R.S., Dekhnich A.V.

Pseudomonas aeruginosa is recognized as one of the six most important pathogens in terms of antimicrobial resistance (“ESKAPE” pathogens), and included by WHO in the group of microorganisms for which the need for development of new antimicrobial agents is crucial. In 2015, P. aeruginosa was the second (after Klebsiella spp.) most common nosocomial bacterial pathogen in Russia with the following resistance rates: amikacin — 45.2%, imipenem — 51.5%, meropenem — 53.3%, colistin — 2.2%, piperacillin/tazobactam — 61.4%, ceftazidime — 56.8%, ciprofloxacin — 61.2%. The majority of carbapenemase-producing isolates in Russia belong to the two epidemic lineages — CC235 and CC654.

Pseudomonas aeruginosa, nosocomial infections, antimicrobial resistance, carbapenemases, CC235, CC654

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):172-180

Current approaches to prophylaxis and treatment of travelers’ diarrhea

Andreeva I.V., Stetsiouk O.U.

Travelers’ diarrhea is the most common infectious disease in this subpopulation and usually develops within the first week of travel. This review presents summarized data on epidemiology and etiology of travelers’ diarrhea. Nonspecific precautions and medical treatments (antimicrobials, probiotics) to prevent this infection are described in detail. Current approaches to the treatment of travelers’ diarrhea (oral rehydration, probiotics, anti-diarrheals, antimicrobials) in adults and children depending on disease severity are also considered.

travelers’ diarrhea, prophylaxis, treatment, antimicrobials, probiotics

Antimicrobials

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):182-191

Susceptibility to antibiotic combinations among nosocomial carbapenemase-producing Gram-negative bacteria isolated in Belarus

Tapalski D.V.

Objective. To assess a susceptibility to antibiotic combinations in nosocomial carbapenemase-producing Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii isolates using a modified method of multiple combination bactericidal testing (MCBT).

Materials and methods. A total of 178 isolates (63 K. pneumoniae isolates, 31 P. aeruginosa isolates, 84 A. baumannii isolates) obtained in the 2013-2017 from hospitalized patients in 28 public health organizations in 4 Belarus regions were included in the study. All isolates were producers of the different carbapenemases (OXA-48, KPC, NDM, VIM, OXA-23, and OXA-40). The susceptibility to antimicrobial agents was determined by an automated method and a broth microdilution method. A modified MCBT method was used for determination of susceptibility to antibiotic combinations. Antibiotic concentrations corresponding to the threshold pharmacokinetic/pharmacodynamics (PK/PD) concentrations for standard doses of antimicrobial agents were used for testing antibiotic combinations. A total of 11 primary and 11 additional antibiotic combinations were tested.

Results. The meropenem MIC values were 4 or more times higher than the threshold PK/PD concentrations for most isolates studied. A total of 42.9% of K. pneumoniae strains, 51.6% of P. aeruginosa strains and 2.4% of A. baumannii strains were non-susceptible to colistin. Using the modified MCBT method, antibiotic combinations with bactericidal activity were detected for 177 (99.4%) isolates; 3 or more antibiotic combinations were bactericidal for 155 isolates (87.1%). The colistin-containing combinations were the most active, including against isolates with colistin MIC values above the threshold PK/PD concentration. The bactericidal activity of meropenem + amikacin and amikacin + levofloxacin combinations against 51.9% of K. pneumoniae colistin-resistant isolates was determined. The meropenem + colistin (85.7%) and imipenem + colistin (84.1%) combinations were the most active against P. aeruginosa. All the colistincontaining combinations were bactericidal against nearly 100% of A. baumannii isolates.

Conclusions. Species-level and strain-level specificity of bactericidal activity for the different antibiotic combinations was found.

Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, antimicrobial resistance, antibiotic combinations, MCBT, bactericidal activity

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):192-197

Comparison of in vitro activity of various macrolides against Helicobacter pylori

Dekhnich N.N., Ivanchik N.V., Kozlov R.S.

Objective. Compare the in vitro activity of clarithromycin, erythromycin, azithromycin and josamycin against the collection of H. pylori strains isolated in 2010–2017 in Smolensk.

Materials and methods. H. pylori strains were collected prospectively from biopsy specimens of the gastric mucosa. Antimicrobial susceptibility testing of H. pylori was performed by the agar dilution method. Interpretation of the results of the susceptibility determination for clarithromycin was carried out in accordance with the recommendations of EUCAST (v 8.0) 2018. The resistance breakpoints for erythromycin, azithromycin, and josamycin were all set at ≥1.0 mg/L. For comparison of the results, the value of the minimal inhibitory concentrations of the tested antibiotic inhibiting the growth of 50% (MIC₅₀) and 90% (MIC₉₀) of H. pylori strains was used.

Results. A total of 276 H. pylori strains were tested. 90% of the MIC values of clarithromycin were in the range from 0.015 to 0.125 mg/l. The percentages of resistance were as follows: clarithromycin 5.1%, azithromycin 7.5%, erythromycin 8%, josamycin 23.2%. Clarithromycin demonstrated significantly higher activity in suppressing the growth of H. pylori strains than azithromycin, erythromycin, and josamycin.

Conclusions. Among the tested macrolide antibiotics maximal anti-H. pylori activity in vitro was observed in clarithromycin.

Helicobacter pylori, antimicrobial resistance, clarithromycin, azithromycin, jozamycin

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):199-204

Erythromycin: safety issues

Matveev A.V., Krasheninnikov A.E., Egorova E.A.

Macrolide antimicrobials are widely used for the treatment of variety of community-acquired bacterial infections. This paper is aimed to review the data on the safety issues of erythromycin. The main attention is paid to the studies on erythromycin prokinetic properties, cardiotoxicity and fetotoxicity.

safety, erythromycin, macrolide antibiotics, cardiotoxicity, prokinetic properties

Antimicrobial Resistance

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):206-215

Antimicrobial susceptibility and association with serotypes of Streptococcus pneumoniae isolates in children with acute otitis media and acute sinusitis in Belarus

Davydov A.V., Titov L.P., Klyuiko N.L., Gurinovich V.V., Lazarev A.V.

Objective. To study antibiotic resistance and its association with serotypes of Streptococcus pneumoniae isolated from hospitalized children with community-acquired ENT infections in Belarus during 2013-2016 and to analyze a potential for the use of different antibiotic classes in the treatment of those infections.

Materials and methods. A total of 115 strains isolated from children with acute otitis media and 18 strains isolated from children with acute rhinosinusitis were tested. Antimicrobial susceptibility testing was performed by a broth microdilution method. Antimicrobial susceptibility testing results were interpreted according to the CLSI 2017 and EUCAST 2017 criteria.

Results. Pneumococcal isolates obtained from the children with acute otitis media have the high rates (50-74%) of non-susceptibility to the majority of beta-lactams, 14-/15-/16-membered macrolides, lincosamides, tetracyclines, folate pathway inhibitors. Rates of non-susceptible to benzylpenicillin, amoxicillin, III-IV generation cephalosporins, and ertapenem isolates were 37-39%. All tested pneumococcal isolates were fully susceptible to fluoroquinolones, ansamycins, glycopeptides, and oxazolidinones. Wild-type strains were rare (13%). MDR and XDR strains were found in 71% and 38% of children, respectively, and belonged to vaccine serotypes, i.e. were fully covered by PCV13 and PPSV23, but partly covered by PCV10 (84% MDR and 80% XDR strains). Pneumococcal isolates from children with acute rhinosinusitis had lower antimicrobial resistance rates and incidence rates of MDR and XDR strains. It can be explained by different serotype distribution in different age-group patients with different types of infection. There were found associations between a patient's age <5 years, “pediatric” serotype, and risk for antibiotic resistant pneumococcal infection.

pneumococcus, Streptococcus pneumoniae, children, acute otitis media, acute bacterial rhinosinusitis, resistance, serotype

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):216-221

Genetic antimicrobial resistance determinants and their prevalence in molecular subtypes of Treponema pallidum subsp. pallidum

Obraztsova O.A., Aleynikova K.A., Obukhov A.P., Kubanov A.A., Deryabin D.G.

Objective. To investigate genetic determinants of resistance to antimicrobial agents recommended for the treatment of syphilis and assess their prevalence in molecular subtypes of Treponema pallidum subsp. pallidum in the Russian Federation over the period of 2014-2017.

Materials and methods. A total of 161 clinical isolates of T. pallidum obtained from Tyva, Stavropol, Irkutsk, Kaluga, Novosibirsk and Omsk regions were included in this study. Genetic material of T. pallidum was detected by PCR with primers to polA gene. Determinants of resistance to penicillins (tromp1, tp47), tetracyclines (16S rRNA) and macrolides (23S rRNA) were determined using the gene sequence analysis. Molecular typing was performed by characterizing variable arp, tpr (E, G, J) and tp0548 genes according to the CDC protocol. Results of this study were compared to historical data on antimicrobial resistance of T. pallidum over the period of 2011-2012.

Results. Analysis of tromp1 and tp47 gene sequences detected C22G and G208T substitutions, respectively. These polymorphisms were not significant for activity of the corresponding proteins, but differed the studied clinical isolates from the reference strain Nichols, therefore, linking them with epidemic genogroup T. pallidum Street Strain 14. Based on the analysis of G1058C mutation in the 16S rRNA gene, all clinical isolates obtained in 2014-2017 belonged to wild type, whereas this genetic determinant of resistance to tetracyclines was determined in 2 of 190 isolates obtained in 2011-2012. Also, A2059G/C mutation in the 23S rRNA gene was not found, whereas a significant A2058G substitution in this gene was determined in 4 isolates obtained in 2014-2017. Results of this study confirm sporadic resistance to macrolides in the Russian Federation, which was previously (2011-2012) found in 3 of 190 isolates of T. pallidum. A2058G mutation was detected predominantly in minor subtypes of T. pallidum (14 b/f, 14 b/g and 14 d/g) and was unrepresentative for molecular subtype 14 d/f which is a predominant one in the Russian Federation.

Conclusions. The long-term use of penicillins for the treatment of syphilis did not result in emergence of T. pallidum resistance to this antibiotic class. An absence of genetic determinants of resistance to tetracyclines confirms them to be second-line drugs. A sporadic prevalence of determinants of resistance to macrolides requires they be used for the treatment of syphilis with caution.

Treponema pallidum, antimicrobial resistance, genetic determinants, molecular typing

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):223-231

Calculation of the optimal structure of antibiotic consumption in a hospital based on the predicted antimicrobial resistance in the treatment of uncomplicated acute pyelonephritis

Gomon Yu.M., Arepeva M.A., Kolbin A.S., Kurylyov A.A., Balykina Yu.E., Proskurin M.A., Sidorenko S.V.

Objective. To select an optimal (in terms of influence on the antibiotic resistance level) and cost-effective structure of antibiotic consumption in a hospital in the management of patients with acute uncomplicated pyelonephritis.

Materials and methods. Based on the literature data as well as a real practice of antibiotic administration, the cost of treatment of an acute uncomplicated pyelonephritis case with different regimens of initial antimicrobial treatment was calculated. Using mathematical modeling, changes in antimicrobial resistance of E. coli taking into consideration the current practice of the antibiotic administration were predicted. The optimal mode of antibiotic consumption in which antimicrobial resistance level would be minimal was predicted.

Results. The current mode of antibiotic consumption where fluoroquinolones, 3rd generation cephalosporins, and penicillin/beta-lactamase inhibitor combinations account for more than 60% of consumption will lead to an increase in the proportion of extended-spectrum beta-lactamase (ESBL) producing E. coli by 14% over a 5-year period. At the same time, alternative (optimal) mode of antibiotic consumption (i.e. almost complete withdrawal of penicillin/beta-lactamase inhibitor combinations and fluoroquinolones from the clinical practice with the concomitant increase in consumption of carbapenems by 30% and increase in consumption of 3rd generation cephalosporins by 20%) will lead to a decrease in the proportion of ESBL-producing E. coli by 7% over 5 years. The cost of an acute uncomplicated pyelonephritis case with the current mode of antibiotic consumption will be increasing due to an increase in the proportion of ESBL-producing E. coli. At the same time, the alternative (optimal) mode of antibiotic consumption will lead to a significant reduction in the proportion of ESBL-producing E. coli.

Conclusions. Use of mathematical modeling gives the opportunity to calculate changes in antimicrobial resistance of pathogens and choose the optimal mode of antibiotic consumption to reduce resistance levels.

antimicrobial resistance, mathematic modelling, antimicrobials, consumption

Personal Experience

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):232-238

Aetiology of hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation

Vasilieva V.A. Parovichnikova E.N., Drokov M.Yu., Kuzmina L.A., Klyasova G.A., Tikhomirov D.S., Tupoleva T.A., Koroleva O.M., Dubnyak D.S., Mikhaltsova E.D., Popova N.N., Konova Z.V., Savchenko V.G.

Incidence, severity, and risk factors for hemorrhagic cystitis (HC) were assessed in 267 patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). HC was diagnosed in 14.6% (39 patients) within 1-139 days after allo-HSCT (median duration – 39 days). Chemotherapy-related HC was diagnosed in 4 patients only. The majority (19/35) of patients developed late HC of viral aetiology. Median time from a day of HC diagnosis to clinical symptoms resolution was 25 days (range: 6 to 133 days). Using a multivariate analysis, allo-HSCT from mismatched unrelated/haploidentical donor was found to be a risk factor of HC (ð=0.01). The analysis also showed that 82.1% of patients with HC received cyclophosphamide as a part of conditioning regimen or +3/+4 days after allo-HSCT.

hemorrhagic cystitis, allogeneic hematopoietic stem cell transplantation, polyomavirus, herpesvirus

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):239-243

Clinical and epidemiological features of infections caused by HHV-6A and HHV-6B

Lysenkova M.Yu., Karazhas N.V., Rybalkina T.N., Veselovsky P.A., Burmistrov E.M., Boshyan R.E., Melekhina E.V., Svitich O.A., Muzyka A.D., Petukhova E.V., Gorelov A.V.

Objective. To determine the detection rates of HHV-6A and HHV-6B compared to other herpes viruses in children of different age groups.

Materials and methods. A total of 128 patients with symptoms of respiratory viral infections (RVI) aged from 1 to 16 years and 101 otherwise healthy children. A comprehensive examination of the patients, including ELISA, indirect immunofluorescence assay, rapid culture method, PCR, and determination of nucleotide sequences of HHV-6 was performed. Children positive for HHV-6 markers (antibodies, early and late antigens) and positive for HHV-6 DNA were selected into one group (n=59), of which 14 children aged from 3 to 10 years were healthy and 45 children (<3 years of age [20 children] and ≥3 years of age [25 children]) had clinical manifestations of RVI.

Results. The incidence rates of acute HHV-6 infection and HHV-6 reactivation were similar between healthy children and children with RVI symptoms (21.9% each). The active Epstein-Barr Virus (EBV) infection took a second place among examined children: acute EBV infection and EBV reactivation were determined in 19 (14.8%) and 10 (7.8%) children, respectively. The incidence rates of HHV-6A and HHV-6B among children with RVI symptoms were similar (55.5% and 42.2%, respectively) whereas HHV-6B was predominant in healthy children (85.7%). The HHV-6A was more common (70%) in children under 3 years of age, but HHV-6B was more frequent (67%) in children aged 3 years and older. The most often initial manifestations of HHV-6A infection were acute fever and catarrhal syndrome; whereas HHV-6B was found more frequently in otherwise healthy children. A sudden exanthema and febrile seizures were significantly more common symptoms in children with HHV-6A infection, whereas tonsillar enlargement with exudate and swollen lymph nodes were observed more frequently in children with HHV-6B infection.

Conclusions. HHV-6A more often causes acute infection in children less than 3 years of age, which is characterized by fever, febrile seizures, rash (roseola), and upper respiratory tract infection with significant catarrhal syndrome. HHV-6B more often causes acute infection in children aged 3 years and older and is rarely presented with specific symptoms of HHV-6 infection, such as sudden exanthema and febrile seizures. HHV-6B is characterized by lymphoid tissue proliferation (tonsillar enlargement and lymphadenopathy) and hepatomegaly in all age groups of children.

human herpes virus 6, HHV-6A, HHV-6B, acute infection, reactivation, children

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):244-248

Local experience of real-time PCR implementation into microbiological monitoring programs

Zykova T.A., Kit O.I., Maslov A.A., Bogomolova O.A., Petrov D.S., Duritskiy M.N.

Objective. To study level and structure of microbial colonization in cancer patients before admission to a surgery department using molecular methods.

Materials and methods. The presence of DNA of methicillin-resistant Staphylococcus aureus, methicillinresistant coagulase-negative staphylococci, Candida albicans / C. glabrata / C. krusei, Acinetobacter baumannii in the clinical specimens and the presence of antimicrobial resistance genes in cultures were detected by multiplex real-time PCR. A total of 741 clinical samples and 313 cultures were studied.

Results. The high level of microbial colonization, including microorganisms with antibiotic resistance genes, was found in cancer patients. Methicillin-resistant staphylococci, A. baumannii and Candida spp. were detected in 56.6%, 20% and 24.8% of cancer patients, respectively. Of patients infected with A. baumannii, 35.9% had OXA-carbapenemase genes. A. baumannii producing bla_OXA40 was the most common cause of infectious complications.

Conclusions. Molecular methods can be used effectively not only for the diagnosis of infectious diseases, but also in microbiological monitoring programs.

molecular methods, realtime PCR, microbiological monitoring, colonization

Clinical Microbiology and Antimicrobial Chemotherapy 2018; 20(3):249-256

Susceptibility to antiseptic preparations in biofilm-forming Staphylococcus aureus and Pseudomonas aeruginosa isolated from burn wounds

Andreeva S.V., Bakhareva L.I., Nokhrin D.Yu., Titova M.V., Khaidarshina N.E., Burmistrova A.L.

The article presents data on susceptibility to antiseptic preparations in antibiotic-resistant S. aureus and P. aeruginosa strains isolated from burn wounds, which were tested in single-species and double-species biofilms with varying degrees (24-hour and 48-hour) of maturity. The studies demonstrated susceptibility of S. aureus and P. aeruginosa in single- and double-species biofilms to “Prontosan”, “Betadine” and “Chlorophyllipt” and resistance to “Miramistin” and “Chlorhexidine”. The bactericidal effect was achieved at concentrations 1.64 times higher than bacteriostatic concentrations for all the antiseptics tested. A double increase in antiseptic resistance level was observed over biofilm maturation process.

S. aureus, P. aeruginosa, burn wounds, biofilm, antiseptic, resistance